<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <button>
        停止定时器
    </button>
    <button>
        停止定时器
    </button>
    <script>
        var btn = document.querySelectorAll('button')

        var Timer1 = setTimeout(function() {
            alert('时间到了')
        }, 2000)

        function callkback() {
            alert('爆炸了')
        }
        var Timer1 = setTimeout(callkback, 5000);
        // clearTimeout(timer)
    </script>
</body>

</html>